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Hey there,

I have a 2002 st4s with 13,000 miles for a number of years and have always had battery problems. 3 seasons ago the dealer installed a battery tender and new battery. Worked great for less than a year, then it would not hold a charge. The dealer has since replaced the battery (no charge) 3 times saying they think they are not charging the battery enough from the start in their shop. The last one I only got a couple of months out of. Any suggestions....I am tired of bundling up in all the cool weather gear, only to have the thing not start.

I only get to ride it once every couple weeks, but keep it on the tender religiously.

Thanks
 

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My '03 is not a daily rider either, but has had no such battery issues. Improper battery activation is certainly a possibility, but if they are eating the cost, you'd think they would have figured that out by now. Is the charging system performing properly? You might temporarily mount a volt meter so you can monitor it and watch for discharge conditions while riding, in case it is intermittent. Have they tried a key-off current draw test to see if some component, or wiring fault is running it down? It is simple enough to do, but you'll need to know the acceptable mA range of draw.
 

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Keeping it on the tender all of the time might be you mistake. Talk to your dealer.

I just put in a new battery in my '03 St4s. My dealer told me to follow all of the instructions in the battery. Fill battery. This can take up to 20 minutes. Then wait between 1 and 2hrs. Let the acid soak into the cells. On the side of the battery is says to charge 1 amp charger fo 10 hrs. Battery works fine.

now to the battery tender.... i told the dealer I was planning to have my 2 amp chrger on a timer, to charge for 1 hr every day.... He said NO! You only have to charge 1 day every 2 weeks. I'm going to give it a try.


Rocketman Bill
 

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Both of my bikes have been on tenders (jr) since day one. The ST still has the oem battery and starts on the first revolution every time.

I'd start looking at the charging system. The '02 had some issues, and it might be over or under charging the battery. Break out the meter and check at the battery, but also have a look at the condition of the pigtail for the regulator. Even if the wires at the regulator look OK the part can still go bad.

Regulators work opposite of a car's alternator, which only produces current when switched on. A bike's regulator has to shunt and dump excess current as heat unless it's used as the charging system works at 100pc all of the time.

Frequently the regulator will eventually fry itself.
 

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Could be some charge problems but please understand that the stock ST battery is a poor make and under rated. There is (IMHO) a lot of guff spoken about this problem WRT upgrading lead etc. A good quality battery with a CCA of 175 + will do the job. I used a Varta with 190 CCA
 

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I changed my original battery last year...only because of its age. It still worked fine. That's over 6 years.
I have a Battery Tender Jr. that I keep connected all of the time.
I would definitely check your charging system.
 

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I just replaced my battery last month, it had the Yuasa YB16AL-A2, but, we took the number to a local Car Quest and they ordered by the Yuasa number.
The battery is exactly the same dimension wise and the bike sure cranks nice now. I nursed that old one along 2 years after I was told it was going.
 

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yep original battery with tender used for last 3 years continuous and only 2-3 times per month ridden.
Can you find a better dealer? The first failure would have warranted a charging system investigation.
 

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MC:
People here suggested looking at the charging system. Read up in the HOW area in DUCATI.MS . Search for "charging" or "alternator".

I recommend you look at the chging voltage. My old ST2 was 14.5V at 2000 RPM (after it "topped up" the battery -- maybe about 2 minutes after starting it). The ST4S I have is closer to 14.0V. So make sure you use a decent digital meter while measuring. Oh, note that at idle, the battery DOES NOT charge, and will sag to about 12V or even less.
So above idle, you should see almost 2V increase. I find it easily seen in the change in headlight intensity at night (a normal phenomina to become familiar with!).

BTW, someone suggested looking at the "off state" discharge current. I believe it's around 2.5mA (that's 0.0025 A) on my ST4S. I measured this this spring after getting the bike (used), and tearing into it a bit.

The battery itself should be a sealed, AGM battery on 2002 and newer DUCs, the older, larger acid type were pre-2001.

I got about 8 years out of my OEM (wet cell) battery on the ST2, using small float chargers, but on a 3 hour "on" period one a day--usually timed just prior to my AM commute...

And the tiny battery that the 2002+ DUCs use...so far, I'm amazed at the cranking power it has for my 996 engine. I swear the 2003 cranks better than the 1998 ever did!
And I had upgraded the starter and gnd. wires on the 1998. Also a huge AGM battery to boot, after 8 years, but it didn't crank as good as my 2003.

FWIW, the AGM batteries usually some fully charged, so maybe your dealer is over charging it?

Also note that people think these are "shunt" RR's. I don't believe they are. The electronics that are imbedded in the RR's nowadays, can switch at speeds that allow them to use only what they need from the large AC voltage that comes out of the stator. Otherwise, these RR's would run screaming hot at light loads (like Lo beam only), and run cooler with added loads (heated gear, hi-beam, etc), but they don't run hotter at low loads....
 
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